soft roe

"Soft roe" is a euphemism for fish sperm, in cases where it is eaten by human beings, by analogy with roe, which is the term for fish eggs when eaten by human beings.

Since fish sperm is, as you might imagine, rather tiny and therefore somewhat hard to keep track of, soft roe is most commonly consumed together with seminal fluid, often while still contained within the fish's spermary organ.